The general objectives of the proposed research are to determine if human locomotion motor patterns can be modified through training and to assess the feasibility of using myoelectrically controlled artificial muscles to assist locomotor movements. We propose to attach lightweight artificial pneumatic muscles to the lower legs of healthy human subjects to characterize how the human nervous system adapts to novel musculoskeletal mechanics. The artificial muscles will be attached to the legs externally via straps on the shank and foot and will be controlled by myoelectrical signals from the subjects' muscles. We will record muscle activation patterns, joint kinematics, and joint kinetics to examine both immediate and long-term motor adaptations to the novel musculoskeletal mechanics. The findings will provide insight into the amount of plasticity within the human locomotion motor pattern and begin to develop myoelectrically controlled artificial muscles as assistance devices for human locomotion.